Virtual Tunnel Development

I am creating the tunnel entrance. I mapped an image to a flat plain and then start moving the verts around till it starts to take shape. Then I start stitching it to the roughed out mountain terrain

Tunnel Wire Mesh

I used the same entrance on both ends to save on recreation

Tunnel Entrance

Shaping up the terrain around the entrance. Notice that the tunnel map has the base green painted in around the rocks. This helps it to blend in with the rest of the mountain texture use around the world.